IMPORTANT- Measurement of the specific latent heat of vaporisation of water

H17 - Specific latent heat of vaporisation of water: How did you make sure that only steam, and not hot water, was added to the calorimeter?

Allow steam to flow for some time before inserting it into water, slope delivery tube back to steam generator, use a steam trap.

H17 - Specific latent heat of vaporisation of water: Why was dry steam used?

Calculations assume that only steam is added, not water.

H17 - Specific latent heat of vaporisation of water: Describe how the mass of the steam was determined.

Final mass of calorimeter plus contents - initial mass of calorimeter and contents.

H17 - Specific latent heat of vaporisation of water: How did you find the mass of steam that was added to the water?

Final mass of water + calorimeter minus initial mass of water + calorimeter

H17 - Specific latent heat of vaporisation of water: Why was a sensitive thermometer used?

For greater accuracy and to reduce percentage error.

H17 - Specific latent heat of vaporisation of water: How was the water cooled below room temperature?

Ice was added to the water.

H17 - Specific latent heat of vaporisation of water: A thermometer with a low heat capacity was used to ensure accuracy. Explain why.

It absorbs little heat from system in calorimeter and calculations assume that no energy is transferred to the thermometer.

H17 - Specific latent heat of vaporisation of water: Give 2 precautions that you took to prevent heat loss from the calorimeter.

• Lagging • Insulation

H17 - Specific latent heat of vaporisation of water: List 3 measurements that you took before adding the steam to the water.

• Mass of calorimeter • Mass of water • Initial + final temperatures

H17 - Specific latent heat of vaporisation of water: Draw a labelled diagram of the apparatus used.

• Stand • Thermometer • Flask • Lagging • Wet steam • Water trap • Dry steam • Calorimeter

H17 - Specific latent heat of vaporisation of water: Give 2 ways of improving the accuracy of the temperature value.

• Use a digital thermometer • Insulation